This is not important. Soon after you close your American Express card account they will notify Priority Pass that the payment card linked to your Lounge Club card is invalid and the Lounge Club card will not work when swiped.
Of course. My question is, what would happen in a rare instance in which a card is not scanned, but just the details are taken?
Not that I am planning to do that, anyway - no lounges at the airports I fly to!